Irritation, inflammation, a slipped or adhered pouch...If intubation has not changed then your pouch probably has not moved...if your output is normal then it may not be pouchitis (it usually changes the quality of the output to either bubbly, liquidy or stinky), it could be a pouch ulcer (you did mention Crohns) or some other kind of irritation...but all of those require either a pouchogram or other sort of exam...
Can you go onto a liquid diet for a few days and see if that helps or not? The post-op BRAT diet works well or just clear soups and apple juice, lots of fluids, rice & toast.
I always start with diet and then keep testing theories until I figure it out...I don't have a doctor that follows me over where I am...
Good luck and let us know what is happening
Sharon